Directional aerial system



. is the provision of an antenna, as

array is indicated as Patented July 31,1945

2,380,519 DIRECTIONAL AERIAL SYSTEM Ohelmsford, England. as-

Ernest Green,

a company of Writtle, signer to Marconis Wireless Telegraph Co. Great Britain Lil,

Application September 30, 1943, Serial No. 504,423

4 Claims.

The present invention relates to directional aerial systems particularly for ultra high frequency operation.

An object of the present invention is the provision of a directional antenna array for ultra high frequency use.

Another object of provision of an antenna, as a simple feeding system.

Still another object of the present invention is the provision of an antenna, as aforesaid, which is of simple mechanical construction.

Still a further object of the present invention aforesaid, which does not have limited directional qualities.

Broadly speaking, there are two systems of directional aerial systems used for ultra high frequency operation, namely "stacked dipoles with reflectors with, usually, primarily excited dipoles and reflectors, and Yagi aerial systems including dipoles with reflectors and directors with primarily excited dipoles and parasitically excited the present invention is the aforesaid, which has reflectors and directors.

The present invention will be completely understood by reference to the following detailed descriptionwhich is accompanied by a drawing in which Figures 1 and 2 illustrate diagrammatically, for the purposes of explanation of the present invention, two lmown types of antenna construction, while Figure 3 illustrates in perspective an embodiment of the present invention, and Figures 4 and 5 illustrate modifications of portions of the embodiment of Figure 3. v

In Figure l, which illustrates a system of stacked dipoles with reflectors, the primarily excited dipole aerials are indlcatedby the reference As, and the primarily excited dipole reflectors are indicated by the reference Rs. The feeder by which the aerials are excited is indicated by the reference Fa, and the feeder by which the reflectors are excited is indicated by reference F1. The spacing between dipoles, of either array is indicated as beingone half the operatingwavelength 2 and the length of each half of any dipole in being. approximately The feeders are crossed over from side to side of their respective arrays, that is correspondin halves of any two adjacent dipoles of either array either Great Britain May 21, 1942 directors are arranged in a v in length. I

system includes a 1 of directors by reference Dr. The feeder by which the dipole aerial isexcited is indicated by reference Fa. The dipole aerials and the reflector and common plane and are each, as indicated, approximately The first system has the advantage of good directional qualities but involves a comparatively complicated feeding system which detracts from simple mechanical construction, and the second system has the advantage of simpler mechanical construction but comparatively limited directional qualities.

The directional aerial system of the present invention has better directional qualities than the Yagi system and is of simpler mechanical construction than the stack dipole system.- It

. may be regarded as a development of either of those systems.

According to the invention, a directional aerial plurality of dipole aerials mounted in spaced relationship relatively to each other with their centres on a common straight line and disposed all in a common plane, there being associated with and disposed parallel to each dipole one reflector and at least one director, all the reflectors being situated on one side of the assemblage of dipole aerials and spaced therefrom and from each other, and all the directors being situated on the other side of the assemblage of dipole aerials and spaced therefrom and from each other, the spacing between adjacent reflecsame as that between adjacent dipoles and wherer in one half of each dipole aerial is connected near its centre to one conductor of a feeder and the other half is connected near its centre to the other conductor of th feeder.

The spacing between adjacent dipole aerials and consequently between adjacentreflectors and between adjacent directors may be substantially half a wavelength at the working frequency and corresponding halves of any two adjacent dipole aerials .be connected to a different one of the conductors of the feeder, or the spacing between adjacent dipole aerials and consequently between adjacent reflectors tors may be substantially a whole wavelength at and between adjacent direc- 'the working frequency and the corresponding halves of all the dipole aerials be connected to the same conductor of the feeder.

The invention is illustrated in Figures 3, 4' and 5 of the accompanying drawing. V In all these flguresthe'dipole aerials are indicated by the reference A1, and the feeder 'by which the dipole aerials are excited is indicated by the reference Fa.

In Figure 3, the reflectors are indicated by the reference Bi, and the directors by the reference Di. The reflectors and directors are not reprod cedin 4 or 5.

in figu refl and 4, the spacing between adjacent dipole aerials and tly that between adjacent reflectors and that between adiacent directors isindicated as being one-half of the operating wave length and corresponding halvesoianytwoadjacentdipoleaerlalsare indicated asbclng w cdi diiferent'one'of theconductors of the feeder Fa. .InFlgure5,thespacingbetweenadjacentdipole aerials and consequently that between adjacent reflectors and that between adjacent directors is indicated as being onewavelength and corresponding halves of any two adjacent dipole aerials are consequently indicatedas being connectedtothesameoneoftheconductorsorthe feeder-FL The dipole aerials At, which ma be adjustableinlengtnandmayconsistofmetalrodsare shown as flxedat cenh'es to a mast or standardMiwhichmaybeofmetalandearthed. TheneflectorsRianddirectorsDLwhichalso adjustable in length and may likewise consistofmetalrodsareshown asflxed attheir centres to brackets Bi which may be of metal and from the mast or standard I In Figures 3. and 5, open wire balanced feeders are indicated. The mast or standard may, however, be a hollow metal tube with the feeder accommodated inside the tube, as indicated'in Figure 4, insulating glands g being provided in the tube whereby connecting stubs 3 may be brought to the outside for connection to the dipole aerials.

The dipole aerials may be disposed horizontally one above the otherand a number of systems are arranged side by side and fed, when the sys, tems are in operation for transmission, in phase.

The lengths of reflector anddirectors and their spacing from their associated dipoles are adjusted to give the required performance; The directors will usually be shorter than a halt wavelength and the spacing from the exciting dipole will be between one-tenth and one-twentieth of the operating wavelength. The reflector will normally be longer than a half. wavelength and the spacing from the exciting dipole will be between one-tenth and one-fifth of the operating wavelength.

What is claimedis:

1. A directional-aerial system including a plurality of dipole aerials mounted in spaced i'elationship relatively to each other 'with their centres on a common straightline and disposed all in a common plane, wherein there is associated .with and disposed parallel to each dipole one refiector and at least one director, all the reflectors being situated one one side of the assemblage of dipole aerials and spaced therefrom and from .each other, and all the directors being situated 5 on the other'side of the assemblage of dipole aerials and spaced therefrom and from each other, the spacing between adjacent reflectors and between adjacent directors being the same as that between adjacent dipoles, and wherein one half of each dipole aerials is connected near its centre to one conductor of a feeder and the other half is connected near its centre to the other conductor 0f the feeder.

2. A system as claimed in claim 1, wherein the spacing between adjacent dipole aerials and consequently between tween adjacent directors is substantially half a wawelengthat the working frequency and corresponding halves of any two adjacent dipole aerials are connected to a different one of the conductors of the feeder. k

3. A directional aerial system including a plurality of dipole aerials conductively mounted in spaced relationship their centres along ing mast and disposed all in a common plane, wherein there is associated with and disposed parallel to each dipole one reflector and at least one director a-ll the reflectors being situated on 0 one side of the assemblage or dipole aerials and spaced therefrom and from each other, and all the directors being situated on the other side of the assemblage of dipole aerials and spaced v therefrom and from each other, the spacing between adjacent reflectors and between adjacent being the same as that between adjacent dipoles, and wherein one half of each dipole aerial is connected near its centre to one conductor of a feeder and the other half is con- 40 nected near its centre to the other conductor of the feeder; said directors and reflectors being conductively mounted on conductive arms at substantially their mid-point, said arms being conductively mounted on said mast.

ralityof dipole aerials conductively mounted in spaced relationship relatively to each other with their cefitres along a common vertical supporting mast'and disposed all in a common plane,

wherein there is associated with and disposed parallel to each dipole one reflector and at least one director, all the reflectors being situated on one side of the assemblage spaced therefrom and from each other, and all the directors being situated on the other side of the assemblage of dipole aerials and spaced therefrom and from each other, the spacing between adjacent reflector-sand between adjacent tor of a feeder and the other half is connected near its centre to the other conductor of the feeder, said mast being hollow, the conductors of said feeder passing longitudinally through the length of said mast. s ERNEST GREEN.

relatively to each other withv a common vertical support 4. A directional aerial system including a plu- I or dipole aerials and 

